---
title: "Code signing custom builds"
---
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

<PlanAvailability slug="all-commercial" />

Code signing is an essential process for ensuring the authenticity and integrity of your custom `Mattermost` builds. This guide provides steps on how to code sign a build using your own certificates for Windows, Mac, and Linux.

<Important>

Make sure to follow each operating system's guidelines and best practices for signing applications.

</Important>

## Prerequisites

<Tabs>
<TabItem value="windows" label="Windows">

1.  **Code Signing Certificate**: Obtain a certificate from a Certificate Authority (CA) or use a self-signed certificate if suitable.
2.  **SignTool**: Available as part of the Windows SDK.

</TabItem>
<TabItem value="linux" label="Linux">

1.  **GPG Key**: Create a GPG key if you don't have one.
2.  **GnuPG**: Install [GnuPG](https://gnupg.org/howtos/card-howto/en/ch02.html) if not already installed.

</TabItem>
<TabItem value="mac" label="Mac">

1.  **Developer ID Application Certificate**: Obtain from Apple. It requires an Apple Developer account.
2.  **Xcode**: Ensure [Xcode](https://developer.apple.com/xcode/) is installed.

</TabItem>
</Tabs>


## Process

<Tabs>
<TabItem value="windows" label="Windows">

1.  **Install SignTool**: Install the Windows SDK to access the `SignTool` utility.

2.  **Obtain a Code Signing Certificate**: Purchase or create a certificate (`.pfx` file) via a CA.

3.  **Import the Certificate**: Open the `.pfx` file and import it into the Windows Certificate Store.

4.  **Sign the Executable**

    - Open the command prompt as Administrator.
    - Use `SignTool` to sign your executable:

    ``` sh
    signtool sign /v /s "My" /sha1 <cert hash> /fd SHA256 /tr http://timestamp.digicert.com /td SHA256 <path-to-your-executable>
    ```

</TabItem>
<TabItem value="linux" label="Linux">

1.  **Create or Import Your GPG Key**: If you don't have a GPG key, create one:

    ``` sh
    gpg --full-generate-key
    ```

    Alternatively, import an existing GPG key, if you have one:

    ``` sh
    gpg --import /path/to/your-key.asc
    ```

2.  **Sign the Package**: Use `dpkg-sig` to sign a Debian package:

    ``` sh
    dpkg-sig --sign builder your-package.deb
    ```

    Use `rpmsign` to sign an RPM package:

    ``` sh
    rpmsign --addsign your-package.rpm
    ```

3.  **Verify the Signature**: Verify the signature of a `.deb` package:

    ``` sh
    dpkg-sig --verify your-package.deb
    ```

    Verify the signature of an `.rpm` package:

    ``` sh
    rpm --checksig your-package.rpm
    ```

</TabItem>
<TabItem value="mac" label="Mac">

1.  **Obtain a Code Signing Certificate**: Create a `Developer ID Application` certificate in your Apple Developer account and download it.

2.  **Import the Certificate**: Double-click the certificate to import it into the Keychain.

3.  **Sign the Application**: Use the `codesign` tool from Xcode to sign your application:

    ``` sh
    codesign --deep --force --verify --verbose --sign "Developer ID Application: Your Name (TeamID)" /path/to/your.app
    ```

4.  \[Optional\] **Verify the Signature**: Verify the signature to ensure everything is correctly signed:

    ``` sh
    spctl --assess --verbose=4 /path/to/your.app
    codesign -dv --verbose=4 /path/to/your.app
    ```

</TabItem>
</Tabs>


## Summary

- **Windows**: Use `SignTool` from the Windows SDK with your imported code signing certificate.
- **Mac**: Use `codesign` and `spctl` tools from Xcode with your Apple Developer ID certificate.
- **Linux**: Use `GnuPG` to create/sign with your GPG key, `dpkg-sig` for `.deb` packages, and `rpmsign` for `.rpm` packages.